1. Field of the Invention
The present invention relates to an improvement of a disk recording device and a disk recording method for recording and erasing titles on, for example, a rewritable optical disk and the like.
2. Description of the Related Art
As is generally known, there have been advances in the technology for high density recording of information, and optical disks having a recording capacity of 4.7 GB (Giga Bytes) for the layer on one surface are put to practical use in recent years.
Examples of this type of optical disk include: DVD-ROM (Digital Versatile Disk-Read Only Memory) for playing-only; rewritable DVD-RAM (Random Access Memory); DVD-RW (Rewritable); and DVD-R (Recordable) on which additional recording can be done, and the like.
However, according to the DVD video specifications, new DVD video titles are always sequentially recorded from the inner periphery side to the outer periphery side of an optical disk so as to be next to the DVD video title that was recorded last. In this case, one DVD video title is recorded in a continuous region on the optical disk and then managed.
In addition, in this type of optical disk, in the case where the last DVD video title that was recorded last is erased, the DVD video title that will be recorded next is overwritten after the DVD video title recorded before the title that was erased, in other words, in the regions where the erased DVD video title was recorded.
Meanwhile, in the case where DVD video titles other than the DVD video title that was recorded last is erased, the region from which the erased title was recorded is not used for recording the new DVD video title, and because this region remains as an empty region, there is a problem that the recording region in the optical disk is not being effectively used.
Jpn. Pat. Appln. KOKAI Publication No. 7-175691 discloses a configuration in which a search is done for the largest continuous empty region of a memory data region and a first cluster is set in the center of the empty region so as to perform data recording, and data recording is thereby performed in continuous clusters, and thus time for recording and playing is shortened.
However, a prerequisite for Jpn. Pat. Appln. KOKAI Publication No. 7-175691 is a recording method in which one group of continuous data is separated into a plurality of clusters and recorded and then managed. According to the specifications for the above-described DVD video, the recording method is such that one title is recorded in a continuous region on the disk and then managed, and there is no disclosure in this publication with respect to effectively using empty regions that are formed discontinuously on the disk as a result of optional erasing of the plurality of titles recorded on the disk.